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The monkeypox outbreak, which health authorities first noticed in Europe in May, is getting worse. According to the latest World Health Organization report, there are over 2,100 confirmed cases and at least one person has died.
Now geneticists finally have enough data to understand exactly how the outbreak began – and where it might be headed.
These are not good news. Monkeypox, a viral disease that causes fever and rash and can be fatal in a small percentage of cases, is endemic to Africa. And now it’s running amok on every other permanently inhabited continent – and evolving rapidly. While public health officials have all the tools they need to contain it – primarily contact tracing and vaccines – the virus is currently moving and adapting faster than we are.
The current strain of monkeypox may have circulated undetected, Months before finally diagnosing the first case outside of Africa. And because there are so many more copies of the virus than we originally anticipated, all mutating separately, this new strain of smallpox could evolve into dangerous new forms at an alarming rate.
“Our data reveal additional clues to ongoing viral evolution and possible human adaptation,” wrote a team led by Joana Isidro, a geneticist at the National Institutes of Health Dr. Ricardo Jorge in Spain, in the new peer-reviewed study published on Friday naturopathy.
A medical lab technician prepares to test suspected monkeypox samples at La Paz Hospital’s microbiology laboratory.
Pablo Blazquez Dominguez/Getty
Monkeypox first made the leap from monkeys or rodents to humans in the Democratic Republic of the Congo in 1970 — and has flared up frequently in Africa since. There are two main tribes, one each in West and Central Africa. The milder West African strain can be fatal in up to 1 percent of cases. The more dangerous Central African strain can kill up to 10 percent of the people it infects.
Smallpox is most commonly spread through close physical contact, particularly sexual contact. It is but not a sexually transmitted disease. It just takes advantage of the skin-to-skin contact that comes with sex. The virus can also travel short distances using spit, although it’s probably not far enough to be considered “airborne”.
Monkeypox occasionally spreads to places where it is not yet endemic. In 2003, 47 people in the United States contracted the West African strain after being exposed to a shipment of pet rodents from Ghana to Texas. A quick response from state and federal health officials — and a few doses of the smallpox vaccine that also works for monkeypox — prevented deaths and temporarily eliminated the virus in the United States
“Because there are so many more copies of the virus than we initially anticipated, all mutating separately, this new strain of smallpox could evolve into dangerous new forms at an alarming rate.”
Officials first noticed the current outbreak, including of the West African tribe, after diagnosing a British traveler returning from Nigeria in early May. Hitchhiking to Europe, the virus spread quickly through physical contact. David Heymann, who used to head the World Health Organization’s emergency department, said men attending raves in Spain and Belgium “amplified” the outbreak – apparently through close, sometimes sexual, contact with other men.
After that, the virus accompanied travelers on planes to distant and distant countries. Doctors diagnosed the first US case on May 27. As of Thursday, the US Centers for Disease Control had counted around 3,500 cases in 44 countries, including 172 in the United States
In the current outbreak, only one person has died from smallpox – in Nigeria. But serious illness and death can delay an actual diagnosis by several weeks, so it’s possible there are many more deaths to come.
Worse, on June 3, the CDC announced that it had found genetic evidence of US smallpox cases that predated the first cases in Europe in May. Because of the similarity between smallpox symptoms and the symptoms of some common STDs, such as herpes, doctors may not have noticed or reported these previous cases at first.
There has been some speculation that the earlier US cases were part of an entirely separate outbreak that happened to overlap with the May outbreak. Isidro and her team sequenced 15 samples from current smallpox patients and concluded that there is only one major outbreak. “All outbreak MPX strains sequenced to date cluster closely together, suggesting that the ongoing outbreak has a single origin,” they wrote, using the scientific acronym for monkeypox.
A passenger walks in front of information about monkeypox virus at Soekarno-Hatta International Airport in Tangerang near Jakarta, Indonesia.
Jepayona Delita/Getty
More precisely, it is less clear if the current outbreak really started. According to Isidro and Co., the virus may have been circulating outside of endemic countries long before officials finally noticed the infections and sounded the alarm. The virus may have traveled beyond Africa in animals such as rodents, spreading from animal to animal before eventually jumping to a human host and triggering the current outbreak sometime before May, the geneticists wrote.
Most likely, however, monkeypox spread from person to person the usual way – and recently Isidro’s team shut down. “Current data points for a scenario with more than one introduction from a single origin, with superspreader events (e.g., saunas used for sexual encounters) and foreign travel likely triggering the rapid global spread.”
In other words, someone – or several people – touched an infected person in Africa, then flew home to Europe or the US and spread the virus to other people through direct contact. The “single source” is the infected human population in Africa. “More than one introduction” means that multiple travelers picked up the same strain of smallpox and spread it beyond Africa at about the same time.
All that is to be said. The May case in the UK was the first infection authorities noticed, but there’s a chance it wasn’t the infection that started the outbreak.
“When you start looking for something, you find it.”
— Michael Wiley, University of Nebraska Medical Center
A particularly worrying possibility is that smallpox is common, if not common circulating to some degree in non-endemic countries, but we rarely notice it unless there’s a large spike in infections, forcing doctors to look more closely at symptoms that could easily be mistaken for something else. Speak, herpes. “When you start looking for something, you find it,” Michael Wiley, a public health expert at the University of Nebraska Medical Center who was not involved in the new study, told The Daily Beast.
In any case, undetected or overlapping transmission vectors are alarming — and not just because they could mean the virus spreading faster to more places before authorities can finally hopefully contain an outbreak. No, multiple introductions also present an opportunity for a virus to mutate more or faster than usual.
In viral diseases, every infected person is a kind of living laboratory – a place where the virus can interact with the antibodies and T-cells of the human immune system and develop countermeasures. The more separate chains of transmission we pass to smallpox, the more likely it is that the virus will mutate along those vectors in some way advantages it and hurts us. For example, the development of resistance to our vaccines and antibodies.
Isidro’s team found 50 single nucleotide polymorphisms, or SNPs, in the monkeypox strain behind the current outbreak. Each SNP is a change in the baseline DNA of a specific organism. Fifty SNPs “are far more (approximately 6-12 times more) than one would expect,” the geneticists wrote. “Such a divergent branch could represent accelerated evolution.”
This does not mean that smallpox itself will learn to develop faster. It’s possible that the current outbreak may have just reached some kind of genetic critical mass before we had a chance to intervene. More infected means more opportunities to evolve, even if the individual mutation rate is the same.
“If I had to guess, I think we could see more drift in terms of the number of mutations based on the size of the outbreak alone,” James Lawler, an infectious disease expert and colleague of Wiley at the University of Nebraska Medical Center, said The Daily Beast. “Drift” is just a fancy term for “increase” in this context.
Monkeypox may have been hiding from our eyes long before we finally noticed it two months ago. Perhaps this strain of the virus was lucky, and more than one traveler almost simultaneously helped spread it outside of Africa. Maybe it’s evolving faster because it’s getting smarter. It’s more likely to change in its current fast clip because there are so many more copies of the virus than we originally anticipated, and each mutating at every opportunity.
It’s all bad news, though – and it should inspire an even greater sense of urgency from health officials as they scramble to diagnose and contain a growing number of cases.
